One of the most important thing people over look is security on their computer physically.  Even though most think no one will every get access to my computer you are wrong!  All you have to do is put a boot up password on your computer which is one of the simplest ways to get around huge problems if someone you don’t want to be on your computer hops on.  They now wont be able to boot from a cd or do anything else without actually knowing your password or taking your computer apart and carrying it off.